Experimental studies were undertaken to determine the mechanical properties of ultra-high strength concrete (water-binder ratio from 15% to 25%) after heating. The following conclusions were obtained. 1) The stress-strain curve after heating is S-shaped with a gradual inclination over 300℃. 2) After heating to over 200℃, Young's modulus decreases rapidly, as does compression strength after heating to over 300℃. 3) Variation of water-binder ratio from 15% to 25% has little effect on the residual values of compressive strength and Young's modulus of the ultra-high strength concrete after heating although the values are influenced to some degree by variations in cement and aggregate. But, the recovery of compressive strength and Young's modulus after two years is negligible compared with normal concrete of high water-binder ratio (60%, 70%).
